Huff Jonathan S, Davis Paul H, Christy Allison, Kellis Donald L, Kandadai Nirmala, Toa Zi S D, Scholes Gregory D, Yurke Bernard, Knowlton William B, Pensack Ryan D
Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States.
J Phys Chem Lett. 2019 May 16;10(10):2386-2392. doi: 10.1021/acs.jpclett.9b00404. Epub 2019 Apr 29.
Molecular excitons are used in a variety of applications including light harvesting, optoelectronics, and nanoscale computing. Controlled aggregation via covalent attachment of dyes to DNA templates is a promising aggregate assembly technique that enables the design of extended dye networks. However, there are few studies of exciton dynamics in DNA-templated dye aggregates. We report time-resolved excited-state dynamics measurements of two cyanine-based dye aggregates, a J-like dimer and an H-like tetramer, formed through DNA-templating of covalently attached dyes. Time-resolved fluorescence and transient absorption indicate that nonradiative decay, in the form of internal conversion, dominates the aggregate ground state recovery dynamics, with singlet exciton lifetimes on the order of tens of picoseconds for the aggregates versus nanoseconds for the monomer. These results highlight the importance of circumventing nonradiative decay pathways in the future design of DNA-templated dye aggregates.
分子激子被用于多种应用，包括光捕获、光电子学和纳米级计算。通过将染料共价连接到DNA模板上进行可控聚集是一种很有前景的聚集体组装技术，它能够设计扩展的染料网络。然而，关于DNA模板化染料聚集体中的激子动力学的研究很少。我们报告了通过共价连接染料的DNA模板化形成的两种基于花青的染料聚集体（一种J型二聚体和一种H型四聚体）的时间分辨激发态动力学测量结果。时间分辨荧光和瞬态吸收表明，以内转换形式的非辐射衰变主导了聚集体基态恢复动力学，聚集体的单重态激子寿命约为几十皮秒，而单体的激子寿命为纳秒级。这些结果突出了在未来DNA模板化染料聚集体设计中规避非辐射衰变途径的重要性。
